Hippuris vulgaris (from Greek: ἵππος – horse and οὐρά – tail), known as mare's-tail[2] or common mare's-tail, is a common aquatic plant of Eurasia and North America ranging from Greenland to the Tibetan Plateau to Arizona.

The common mare's tail is a creeping, perennial herb, found in shallow waters and mud flats.

Studies of H. vulgaris in the Tibetan Plateau have shown that it is a prolific methane emitter.

[3] The roots of H. vulgaris extend into the anoxic zone of wetland soils and create a conduit for methane produced in the anoxic zone to travel to the atmosphere.

[citation needed] It can also be a troublesome weed, obstructing the flow of water in rivers and ditches.